1. Field of the Invention
This invention provides novel fiber-forming, melt-spinnable wholly aromatic copolyesters prepared from certain monosubstituted hydroquinones, terephthalic acid and a member of the group consisting of 3,4'-dicarboxydiphenyl ether, 3,4'-dihydroxydiphenyl ether, 3-hydroxy-4'-carboxydiphenyl ether and 4-hydroxy-3'-carboxydiphenyl ether. These copolyesters are useful for preparation of filaments having high tenacity and/or high modulus. They are also useful for extrusion molded or injection molded products and for preparation of tough films.
2. Description of the Prior Art
Aromatic copolyesters capable of forming optically anisotropic melts are well known in the art. These polymers have yielded heat-treated fibers with properties that are especially useful in tire cords or drive belts. The provision of novel copolyesters for these purposes is deemed a worthwhile objective.